This invention relates to earth boring by the rotary system as it is employed typically in drilling petroleum wells. More particularly the invention relates to a drill pipe comprising a tube having tool joints welded to its ends and a wear belt about the tube between its ends, and to method of making such a drill pipe.
For a discussion of the problems encountered in attaching a wear belt to a drill pipe, reference may be made to prior U.S. Pat. No. 3,697,141 -- Garrett.
Among the difficulties with prior art wear belts may be mentioned the inability of rubber jackets to last very long in open hole because of cutting, the injurious effect of metal sleeves applied directly to drill pipe because of stress concentration, the expense of assembling and welding more complex structures, and the tendency of some wear belts to become knocked loose or twisted loose upon the drill pipe and slide therealong from the middle of the pipe toward a tool joint at one end of the pipe where the belt has reduced utility. It is an object of the invention to overcome the aforementioned problems and to provide at minimum expense a drill pipe incorporating a long lasting, well secured wear belt.